After I mount the setup iso image as a new drive and run setup.exe file

How to solve incorrect function installation error?
I overcome this setup issue by extracting the contents of the setup .iso file SQLServer2014CTP2-x64-ENU.iso into a new local folder.
After extraction of all files of the installation disc image is completed, I run the setup.exe file within the new folder.
Then the setup continues without any error.

To summarize, to resolve "incorrect function" setup error for SQL Server 2014 CTP2 from installation disc image file SQLServer2014CTP2-x64-ENU.iso, extract .iso file contents into a new folder and start setup.exe from this new file folder.